Synthetic resin and process for making the same



Patented Aug. 5, 1941 UNITED STATES SYNTHETIQRESIN AND PROCESS FOR v MAKING THE SAME Frank J. Soday, Swarthmore, Pa., assignor to Th United Gas Improvement Company, a corpora tion of Pennsylvania No Drawing. Application January 31, 1941, Serial No. 376,851

. 8 Claims. (Cl. 260-22) This invention relates to new resinous materials. More particularly it relates to new resins ll H2 its anhydride, 3-methyl-A4-tetrahydrophthalic anhydride, having the following tructural formula: 4

OH; F C C/.

is the equivalent of the acid in the preparation of the resin disclosed herein.

It has now been found that 3-methyl-A4-tetra hydrophthalic anhydride or 3-methyl-A4-tetrahydrophthalicacid, or mixtures containing both the anhydride and the acid, may be converted into alkyd resins of excellent quality by reaction with polyhydric alcohols. Polyhydric alcohols are those containing more than one hydroxyl group, such as, for example, ethylene glycol, and glycerol, as well as polyglycols and polyglycerols.

The reaction .of 3-methyl-A4-tetrahydrophthalic anhydride, or 3-methyl-A4-tetrahydrophthalic acid, or mixtures containing both the anhydride and the acid, with polyhydric alcohols is quite unique in thatit is completed in a. surprisingly short period of time. Whereas, the condensation of the polycarboxylic acids, or anhydrides, or mixtures thereof, with polyhydric alcohols to give resins with suitable melting points has heretofore required heating the reactants for a period of several hours, the condensation of 3-methyl- A4-tetrahydrophthalic anhydride, or 3-methyl- A4-tetrahydrophthalic acid, or mixtures of the acid and anhydride, with polyhydrlc' alcohols can be completed wtihin a relatively short period of time, and incertain cases, can be completed within a few minutes. This factor is of the greatest practical importance as it enables the resin or varnish manufacturer to prepare substantially larger quantities of resin or varnish in existing equipment without additional capital expenditures.

This property is of special significance from the standpoint of the preparation of oil varnishes, as it enables one to prepare varnishes of this type by the reaction of the acid'or anhydride, or mixtures of the acid and anhydride, with the desired polyhydric alcohol in the presence of drying oils or mixtures of drying oils without danger of jelling these oils by prolonged heating at elevated temperatures. In fact, the oils may be bodied to a considerable extent prior to the additionof the acid or anhydride or mixture of the acid and anhydride, and the desired polyhydric alcohol, after which these reactants may be added to the bodied oils. I The heating is continued for a relatively short additional period of time followed by chilling the varnish cook in the usual manner.

This method of preparing alkyd-type varnishes is of advantage from the standpoint of the possibilityof exercising close control over each step of the reaction.

The rate of reaction of 3-methyl-A4-tetrahydrophthalic acid, or anhydride, or mixture of acid and anhydride, is quite pronounced in the case of polyhydric alcohols containing more than two carbon atoms.

In addition to possessing the advantage of reacting at an unusually rapid rate, 3-methyl-A4- tetrahydrophthalic anhydride or 3-methyl-A4- tetrahydrophthalic acid, or mixtures of the acid and anhydride, are also outstanding from the standpoint of the preparation of light colored alkyd-resins. The resins prepared by the reaction of the acid or anhydride or mixtures of .the acid and anhydride, with polyhydric alcohols are unusually clear, transparent, and light in. color.

This is of particular advantage from the standpoint of the preparation of decorative finishes, such asvarnishes, lacquers or enamels, which are to be used for coating furniture, or for interior applications in general.

The resins obtained by the reaction of polyhydroxy alcohols with 3-methyl-A4-tetrahydrophthalic acid or its anhydride may be classified as (1). non-convertible resins, (2) heat convertible resins, and (3) element convertible resins.

Non-convertible resins are those which remain fusible at all stages but the viscosity of which increases with-increase in heating time and/or temperature used in the production of the resins.

The heat convertible resins are those which become infusible and insoluble by heat treatment during or after formation.

The element convertible resins are those which harden into relatively infusible and insoluble products by the addition, usually gradual, of

. other elements, for example, oxygen from the air.

It has been found that the first two types of these resins may be prepared through the reaction of different polyhydric alcohols with 3-m.ethyl-A4-tetrahydrophthalic acid, its anhydride, or mixtures of the acid and the anhydride, and that the third type may be prepared by reacting either of the first two types further, such as with an unsaturated monobasic acid.

It is an object of this invention to provide new synthetic resins of desirable properties. It is ,a further object of this invention to provide alkyd resins of (1) non-convertible, (2) heat convertible and (3) element convertible types. Another object of this invention is to provide unusually reactive polycarboxylic acids or anhydrides for the preparation of alkyd-type resins. It is also an object of this invention to provide resins of unusually light color and transparency. A further object of this invention is to provide new compositions of matter by the reaction of 3-methyl-A4-tetrahydrophthalic acid or its anhydride with polyhydric alcohols. Another objectof this inventionis to provide resins of desired solubility characteristics, desired acid numbers, desired melting points, desired fluidity or plasticity, desired color, desired compatibility with drying oils, and useful for desired purposes. More specifically, it is an object of this invention to provide new synthetic resins which may be used for molding, casting, mechanical forming or machining operations, for the preparation of desired articles, either alone or in admixture with other resins, and either with or without the use of dyes, pigments, plasticizers, diluents, molding lubricants, fillers, or the like. Other more specific objects of this invention are to provide new resinous compositions which may be used in the textile fields for sizing, waterproofing, the production of crease-proof or wrinkle-proof fabrics, as well as for the production of threads, filaments, wool-like masses, porous objects or masses, and the like. A still further specific object is the provision of new compositions which may be used for insulating purposes, for the preparation of protective and decorative coatings in the form of spirit varnishes, oil varnishes, enamels, lacquers, paints and similar compositions, and the provision of driers for coating compositions. Other objects of this invention will becme apparent to those skilled in the art upon becoming familiar herewith.

3-methyl-A4-tetrahydrophthalic acid or its anhydride may be obtained in a number of ways.

For example, the anhydride may be prepared through the reaction of piperylene with maleic The anhydride may be readily hydrolyzed to form the corresponding'acid, 3-methyl-A4-tetrahydrophthalic acid, for instance, by mixture'with water.

Illustrative of the reaction by which B-methyl- A4-tetrahydrophthalic anhydride may be prepared is the example given below as Example 1.

Piperylene or hydrocarbon fractions containing any portion of piperylene may be used to react with maleic anhydride. The piperylene may be obtained. synthetically, or from fractions obtained by condensation in the manufacture of carburetted water gas, oil gas, refinery gas, or coke oven gas, or from similar sources. Such fractions will be referred to herein generally as light oil fractions.

For example, a sample of light oil obtained in the manufacture of oil gas" under certain conditions, may be fractionated to obtain a cut containing up to approximately to say approximately from 30 to 85% piperylene, in addition to various quantities of other unsaturated hydrocarbons. Cyclopentadiene and perhaps similar unsaturated hydrocarbons which may be present in a piperylene fraction may, if desired, be removed among other ways by heating the material, say at C., in a closed vessel for several hours, followed by the distillation of the unchanged piperylene from the polymers thus formed. Isoprene may also be present. While a concentration of piperylene of at least 30% is preferred, lower concentrations may be employed.

The piperylene or piperylene fraction may be reacted with maleic anhydride or maleic acid or mixtures of these to produce 3-methyl-A4- tetrahydrophthalic anhydride by warming a mixture of the reagents. The reactants may be mixed say in substantially molar quantitie and allowed to react at room temperatures or at elevated temperatures until substantially complete conversion has been obtained.

A preferred embodiment of efi'ecting the reaction is to mix the reactants and allow the mixture to stand at 0 C., or below, for a period of time.

However, the process is not restricted to the use of any definite reaction time or temperature.

The reactants may be combined as such, or

- in solution form in a suitable solvent or solvents.

Suitable solvents for this purpose include aromatic hydrocarbons, chlorinated solvents, esters, ethers, and the like.

, 3-methyl-A4-tetrahydrophthalic anhydride is obtained in good yield as a result of this reaction. The anhydride may be readily hydrolyzed to 3-rnethyl-e4-tetrahydrophthalic acid if desired as above pointed out.

Illustrative of one of the methods of preparation of 3-methyl-A4-tetrahydrophthalic anhydride is the following example:

EXAMPLE 1 An enameled vessel of about five gallons capacity was equipped with a stirrer, safety valve, and manometer. A mixture of 1475 grams (15.06

mols) of maleic anhydride and 1589 grams (2270 cc.) of a piperylene cut containing 83.7% piperylene by weight (19.6 mols. of piperylene) was placed in the vessel, together with one liter of acetone.

The temperature was reduced to 0 C. and the mixture stirred for a period of one hour, whereupon an exothermic reaction occurred.

The mixture was maintained at a temperature of 0 C. for an additional period of 48 hours, after which the solution was decanted from the crystalline 3-methy1-A4-tetrahydrophthalic anydride.

The crystals obtained amounted to 1673 grams,

Resin formation The formation of the herein described resins is in general carried out-by mixing the 3-methyl- A4-tetrahydrophthalic acid or its anhydride with a polyhydric alcohol and heating at a temperature sufficient to eifect condensation of the reactants.

In general, it has been found preferable to employ 3-methyl-A4-tetrahydrophthalic anhydride instead of the acid, although the latter may also be used with good results.

The heating is continued until a resin of the desired consistency or degree of hardness is obtained. The temperature and time of reaction will vary with the particular alcohol used and with the nature of the resin desired. In general, a temperature approximating the boiling point of .the alcohol is preferably employed, because this affords a close control of temperature, the volatilized materials being condensed and returned to'the sphere of the reaction.

Higher temperatures may be used, if desired,

by the application of sufiicient pressure to prevent excessive volatilization of any of the re actants. As an example, the materials may be heated in a closed container.

The characteristics of the finished resin will vary with the heating time and the temperature employed. A longer period of heating or a higher reaction temperature, or both, will result in the production of a resin ofincreased viscosity.

Solubility of the resultant resin in organic solvents may be decreased and hardness increased by an increase in length of heating time or an increase in the reaction temperature, or both.

Solubility may, on the other hand, be increased by modifying the resins in a manner to be described hereinafter.

The proportions of the reactants used to produce the herein described resins may be varied over very wide limits. The resins formed by the reaction are removed from the unreacted portions of either component at the end of the desired reaction period, preferably by distillation, although other separation methods may be employed.

Catalysts, or other modifying agents, such as retarding agents, may be used to accelerate or retard the rate of reaction, if desired.

Examples of catalysts are sulfonic acids, such as benzene sulfonic acid,1-naphthylamine-4-su1- fonic acid, and -aminotoluene-Z-sulfonic acid, metallic soaps, such as cobalt linoleate, lead oleate, and aluminum stearate, and contact materials such as silica gel.

Examples of retarding agents are naphthalene, tetrachloro-naphthalene, boric acid, urea, or thiourea.

As above pointed out, three general types of resinous compounds may be prepared in accordance with this invention.

Nonconvertible resins A series of resins which are preponderately of the non-convertible type may, in general, be prepared by the reaction of dihydroxy alcohols, that Examples of glycols which may be used are ethylene glycol, propylene glycol, trimethylene glycol, alpha butylene glycol, beta butylene glycol, butanediol-1,3, tetramethylene glycol andsimilar compounds.

Examples of polyglycols which may be used are diethylene glycol, triethylene glycol, tetraethylene glycol, and higher members of the series, as well as polyglycols prepared from glycols other than ethylene glycol.

Examples of substituted polyhydroxy alcohols having two hydroxy groups and polymeric forms thereof that may be used are glycerol monomethyl ethers, 1-ch1oropropandiol-2,3, glycerol monoethyl ether, a-glycerol phenyl ether, tetrahydrofurfuryl ether of glycerol and polyglycerolmonomethyl ether.

The modified glycols, namely polyglycols and polymeric substituted glycols, may be used as such or they may be generated in situ. This applies as well to any of the alcohols to which this invention relates.

The products obtained when dihydroxy alcohols are employed are, in general, flexible, and are compatible with plastics such as nitrocellulose and cellulose acetate plastics. They may, therefore, be used, among other things, to improve the gloss and adhesion of lacquers containing one or 'both of these materials.

Mixtures of any of the foregoing alcohols may be employed, if desired.

Illustrative of the preparation of a new resin through the reaction of 3-methy1-A4-tetrahydrophthalic acid or its anhydride and a glycol, is the following example:

EXAMPLE 2 A mixture of 1.1 mols of ethylene glycol and 1 1 mol of 3-methyl-A4-tetrahydrophthalic anhydride was placed in a closed container provided with a reflux condenser and heated for a period of 15 minutes at a temperature of 290 C.

The product was a solid alkyd-type resin, ligh yellow in color and slightly tacky. It is readily incorporated in standard paint or varnish formulations.

Heat convertible resins due to its ready availability and comparatively low cost.

Examples of other alcohols which may be used to prepare this type of resin are the following: pentaerythritol, sorbitol, mannitol, butanetriol- 1,2,3, and similar compounds as well as polymeric forms thereof including the polymeric forms of glycerol, namely polyglycerols.

It has been found that the resins prepared through the use of polyglycerols have, in general, the same physical properties as those prepared from normal glycerol.

The polyglycerols may be prepared by heating glycerol for a suitable period of time, either with or without the addition of a suitable catalyst such as sodium hydroxide.

Substituted polyhydroxy alcohols having three or more hydroxy groups, and polymeric forms thereof, may also be employed. An example of such an alcohol is mono butyl erythritol.

Mixtures of any of the foregoing alcohols may be employed, if desired.

Illustrative of the preparation of this type of resin are the following examples:

EXAMPLE 3 One mole of 3-methyl-A4-tetrahydrophthalic anhydride was mixed with 1 mole of glycerine. The mixture was rapidly heated to a temperature of approximately 290 C. and held at this point for a period of minutes. There was obtained as a product, a very light colored, non-tacky resin of unusually high optical refractivity.

This resin was tested in various coating compositions and was found to possess very good coating properties. It produced a film which retained the properties of the original resin and which became hardened by the application of heat.

EXAMPLE 4 Three moles of 3-methyl-A4-tetrahydrophthalic acid was mixed with 2 moles of glycerine. The mixture was heated to a temperature of approximately 290 C., and held at this point for a period of 12 minutes.

There was obtained as a product a high melting, light colored, non-tacky resin of unusual brilliance.

The resin obtained from this reaction was found to be particularly suitable for use in coating compositions and as an ingredient in molding powders.

Element convertible'resins A series of resins which are preponderately of the element convertible type may be prepared from the resins so far described. The resins of this series harden in most instances quite rapidly and become relatively infusible and insoluble on exposure to the air. The majority of these resins are of the oxygen convertible type which harden by the gradual addition of oxygen from the air. The others for the most part harden by gradual addition of other constituents present in atmospheric air.

The element convertible resins may be prepared by modifying the foregoing alkyd resins by the addition of unsaturated monobasic acids. A methyl tetrahydrophthalic acid resin, such as those the preparation of which has already been described, will react withunsaturated monobasic acids, and particularly those contained in drying oils, with the resultant formation of a compound containing the drying oil component in chemical combination with the resin molecule.

Either the drying oils themselves or'the drying seed oil, rubberseed oil, and similar vegetable drying oils. It has been found that a mixture of a drying oil and one or more fatty acids derived from drying oil can be more readily incorporated with the methyl tetrahydrophthalic acid resin than either of the components taken alone. The

fatty acid derived from the same drying oil is preferred. However, any mixture of drying oils,

or any mixture of fatty acids, or both, may be employed without departing from the broad concept of the invention.

The drying oil, the unsaturated fatty acid, or their mixture may be incorporated with the resin at any stage that is, before, during, or after its formation. In the case of the heat convertible resins this should preferably take place prior to any substantial conversion and especially before complete conversion to the insoluble form.

An example wherein a drying oil is incorporated during the initial resiniflcation reaction is as follows:

EXAMPLE 5 Approximately 10 parts of linseed oil were heated to 350 F. in a closed container provided with an agitating device. At this point 25 parts of ethylene glycol were added and the temperature.

raised to 400 F. Approximately, 0.0040 part of litharge were then added as an accelerator and the mixture held at this temperature (:10" F.) for /2 hour. The ethylene glycol volatilized during this procedure was continuously returned to the reaction vessel by means of a suitable condenser.

The solution was then allowed to cool to 200 F., and 1.7 parts of ethylene glycol, together with 8.6 parts of 3-methyl-A4-tetrahydrophthalic anhydride, were added. The temperature was carefully raised to 350 F. over a /2 hour period. At this point a steady stream of CO2 was bubbled through the reacting mixture to remove any wa-.- ter formed during the reaction. The temperature was then raised to 390 F. (i10 F.) and held at approximately that temperature for 10 hours.

The resulting alkyd-type resin was poured while hot into 1.0 parts of xylol, under constant agitation, followed by the addition of 7 more parts of xylol.

Other procedures may be adopted.

The product obtained is a clear varnish possessing excellent coating properties.

Wood or metal panels coated with thisvarnish air dry in a relatively short period of time to form a hard, mar-resistant, flexible, adhering film.

Metal panels, such as for example tin plate, may be coated with this varnish, and if desired, the varnish film hardened by baking. A suitable. temperature is 350 F. and the panel may be baked at this temperature for a period of 30 minutes to one hour. The film obtained is very hard and mar-resistant, flexible and extensible, and adheres very tenaciously to the metal surface.

Varnishes of this type may be used for either the prime coat or the top coat, or both, or in one or more coats, on food and beverage cans, as for example, beer cans, and cans for vegetables and fruits.

Miscellaneous resins A resin having improved solubility maybe prepared by reacting 3-methylA4-tetrahydro- .phthalic acid or its anhydride with a substituted polyhydroxy alcohol having at least two hydroxy groups per molecule still available for reaction.

As a rule the longer the unhydroxylated chain of such an alcohol the greater the solubility of the resin formed. This applies to both the non-convertible type of resin and the heat convertible type proved solubility and low acid number may be prepared through the reaction of a mixture of any of the polyhydroxy alcohols, or substituted polyhydroxy alcohols, or modified polyhydroxy alcohols, or two or more of the foregoing, with 3-methyl-A4tetrahydrophthalic acid or its anhydride.

A polyhydroxy alcohol which has been heat treated or otherwise polymerized to yield polymeric alcohol or alcohols is considered a modified polyhydroxy alcohol. Examples are polyglycols and polyglycerols, and polymeric forms of substituted polyhydroxy alcohols.

An example of a resin of this character is that produced through the reaction of a mixture of ethylene glycol and glycerine with 3-methyl-A4- tetrahydrophthalic anhydride.

Resins having special application in the protective coating field, because of their lower melting points and other desirable properties, may be prepared by reacting mixtures of monohydric alcohols and polyhydric alcohols, including substituted and modified polyhydroxy alcohols, and mixtures of any of the foregoing polyhydroxy alcohols whether substituted or modified or not, with B-methyl-A'i-tetrahydrophthalic acid or its anhydride.

An example of a resin of this character is that produced by the reaction of 3-methyl-A4- tetrahydrophthalic anhydride with a mixture of glycerol and a relatively small quantity of butyl alcohol.

, If desired, the monohydric and polyhydric alcohols may be added in sequence, either immediately in sequence or after the alcohol of the preceding addition has/ reacted to some extent.

The resulting resins are particularly tough and have excellent coating properties.

Resins having low melting points and other desirable properties may be prepared through the reaction of 3-methyl-A i-tetrahydrophthalic acid or its anhydride directly with certain substituted alcohols, for example, alcohol amines such as monoethanol amine, diethanol amine, triethanolamine, and similar compounds, or mixtures of the same.

It has been found possible to produce resins having increased solubility and compatibility, useful generally in coating compositions and particularly in nitrocellulose or other lacquers, by

modifying any of the 3-methyl-A4-tetrahydrophthalic acid resins described herein with monobasic acids generally, It will, of course, be understood that the treatment of heat convertible resins preferably takes place before any degree of conversion to the insoluble form is effected. With unsaturated monobasic acids, the

resins will, in general,.also be element convertisuch, it. is preferred generally to use the free acids derived from these oils since it is often dlflicult to incorporate the glyceride oils in an alkyd resin by direct methods.

Other monobasic acids which may be used to modify the properties of resins described herein include certain natural resins such as rosin, copal, kauri, and the like. The use of these compounds increases the solubility and other desirable properties of the resins.

.Resins having particular use in quick drying varnishes may beprepared by modifying any of the resins described herein with a drying oil or oils of a non-acid character. Generally speaking, these oils are synthetically prepared and as a rule are considered to be of hydrocarbon constitution.

Resins having particular application in molding compositions and in the protective coating field may be prepared by modifying any of the resins described herein with other synthetic resin such as synthetic resins of the phenolformaldehyde type, of the urea-formaldehyde type, of the polystyrene type, and of the polyindene type. Resins prepared in this manner possess the superior flexibility of the alkyd-type resins and the hardness of the synthetic resins.

Alkyd-type prepared from 3-methyl-A4-tetrahydrophthalic anhydride, or the'corresponding acid, as for example, resins prepared according to the method disclosed in Example 2, but with on the other.

the use of shorter heating periods may be readily incorporated in standard varnish or paint formulations. The following is an example:

EXAMPLE 6 Parts Resin 12.2 China wood oil 14.0 Solvent naphtha (VMM. & P.) 26.2 Drier 1.0

The mixture of resin and China wood oil is heated in a copper vessel to a temperature of 400 F. during a period of 20 minutes. The mixture then is heated to a temperature of 560 F. during a period of 10 minutes, and held at this temperature for an additional period of 3 minutes. It is allowed to cool at 535 F., held at this temperature for a period of 6 minutes, chilled to 400 F. and reduced with solvent naphtha. The drier is stirred into the varnish whenever it reaches room temperature,

The product is a clear, light colored varnish with excellent coating properties.

Standard varnish procedure may be adopted in the preparation of various coating compositions. a

It will, of course, be understood that the physical properties of any of the foregoing resins may be modified to a certain extent by variation of the quantities of reactants employed. For instance, one may expect to find some difference in physical properties when the reactants are used in molar quantities on the one hand, and when molar quantities are widely departed from example, maleic anhydride, phthalic anhydride,

or similar substances may be added at any stage of the resinification reaction without departing from the general principles of the invention.

Moreover, since piperylene fractions employed in the manufacture of methyl tetrahydrophthalic anhydride may contain other unsaturated materials capable of reacting with maleic anhydride to form adducts, which in turn are capable of forming resins with polyhydric alcohols, 50- that the overall reaction results in mixed resins, the invention in its broadest aspects is intended to cover such procedure and the products obtained.

An example of a material which might be present in a piperylene fraction is a lesser quantity of ,isoprene. As described and claimed in my copending application Serial Number 238,384, filed November 2, 1938, this material is capable of reaction with maleic anhydride to form a compound which in turn reacts with polyhydric alcohols generally to form resins.

When this material is present in the piperylene a mixed resin is obtained.

Resins prepared in accordance with my invention are useful generally in coating compositions for application to all types of materials whether of metal, wood, glass, ceramic substances or otherwise.

Such coating compositions may be made by merely dissolving any of my resins in a suitable solvent of which benzene, toluene, xylene, ethyl benzene, solvent naphtha, petroleum naphtha. carbon tetrachloride, decalin, triethylbenzene and ethylene dichloride are examples.

On the other hand, my resins may be incorporated in varnishes as illustrated above or in paints, lacquers, enamels, or other coating materials.

These coating materials are useful in coating metal beverage and food containers such as the container commonly known as the tin can. This.

applies particularly to coating compositions made 'by dissolving my resins in solvents or by incorporating my resins in varnishes. The adherence to the metal is unusually tenacious.

The term resin modifying agent as used herein is, in general, intended to mean an agent which is added to modify the resin resulting from reacting a polyhydric alcohol with 3-methyl-A4- tetrahydrophthalic acid or anhydride, or a mixture of the two.

The resin modifying agents particularly described herein, include monobasic acids generally. Among these monobasic acids 'are the unsaturated and saturated acids obtained from drying oils, non-drying oils, and natural resins, as well as the drying oils, non-drying oils and natural resins themselves.

Resin modifying agents disclosed herein also include the monohydric alcohols whether substituted or not.

Other synthetic resins and non-acid drying oils are also included.

Whereas, the monobasic acids and the monohydric alcohols are largely employed to directly modify the reaction product of a polyhydric alcohol and 3-methyl-A4-tetrahydrophthalic acid or anhydride, in the case of other synthetic resins or non-acid drying oils the addition may be made either directly. or with or without, or before or after, the addition of monobasic acid or monohydric alcohol.

Furthermore, synthetic resin and non-acid drying oil may each beadded without the other.

In general, the modifying agents are added before or during the initial resinification reaction. However, in certain cases, such as with other synthetic resins, or non-acid drying oils, or both, the addition may be made. if desired, after the initial resinification reaction is complete, in which case steps are preferably taken such as by heating to cause a secondary resinification reaction to take place. When both synthetic resin and non-acid drying oil are employed, the addition of synthetic resin may precede or follow or be made simultaneously with the addition of non-acid drying oil.

In the specification and in the claims, the following terms have the following meanings:

The tdrm 3-methyl-A4-tetrahydrophthali acid is intended to embrace the acid or its anhydride or a mixture of the two.

The term fpolyhydric alcohol, or its equivalent, as used in the specification and in the claims, is intended to embrace any organic compound containing at least two hydroxyl groups each of which is attached to a carbon atom which is non-aromatic in nature. By the term carbon atom which is non-aromatic in nature is meant a carbon atom which is not contained in a homocyclic or heterocyclic aromatic ring.

By the term substituted glycol is meant any polyhydric alcohol containing only two hydroxyl groups and at least one other substituent group such as ether, ester, amino, aldehyde, ketone, or halogen.

By the term modified glycol is meant a compound obtained by the polymerization or condensation of any polyhydric alcohol containing only two hydroxyl groups.

By the term substituted compound having more than two hydroxyl groups is meant a polyhydric alcohol containing more than two hy- 5 piperylene and derived from light oil obtained droxyl groups and at least one other substituent group such as ether, ester, amino, aldehyde, ketone or halogen.

By the term modified compound having more than two hydroxyl groups is meant a compound obtained by the polymerization or condensation of any polyhydric alcohol containing more than two hydroxyl groups.

By the term monohydric alcohol is meant any alcohol having only one hydroxyl group.

By the term substituted monohydric alcohol is meant an alcohol containing only one hydroxyl group and at least one other substituent group such as ether, ester, amino, aldehyde, ketone or halogen.

While resins of particular types and procedures for the purpose of preparing such resins have been particularly described, it is to be understood that this is by way of illustration only. Therefore, changes, omissions, additions, substitutions and/or modifications may be made within the scope of the claims without departing from the spirit of the invention which is intended only as required by prior art.

This application is a, continuation-in-part of my copending application Serial Number 244,349, filed December 7, 1938.

I claim:

1. A synthetic resin comprising the reaction product of a polyhydric alcohol, the adduct 01 maleic anhydride with a piperylene fraction containing up to approximately 90% piperylene and derived from light oil obtained in the manufactureof combustible gas and in which fraction piperylene is the predominant diolefine constituent, and at least one of a group consisting of drying oil and drying oil acid.

2. A synthetic resin comprising the reaction product of-a polyhydric alcohol, the adduct of maleic anhydride with a piperylene fraction containing between approximately 30% to in the manufacture of combustible gas and in which fraction piperylene is the predominant diolefine constituent, and at least one of a group consisting of drying oil and drying oil acid.

3. A synthetic resin comprising the reaction product of ethylene glycol, the adduct of maleic anhydride with a piperylene fraction containing up to approximately 90% piperylene and derived from light oil obtained in the manufacture of combustible gas and in which fraction piperylene is the predominant diolefine constituent, and at least one of a group consisting of drying oil and drying-oil acid.

4. A synthetic resin comprising the reaction product of glycerol, the adduct of maleic anhyd ride with a piperylene fraction containing up to approximately 90% piperylene and derived from light oil obtained in the manufacture of combustible gas and in which fraction piperylene is-the predominant diolefine constituent, and at least ,one of a group consisting of drying oil and drying oil acid.

5. A process for the preparation of a synthetic resin comprising reacting a polyhydric alcohol,

the adduct of maleic anhydride with a piperylene fraction containing up to approximately 90% piperylene and derived from light oil obtained in the manufacture of combustible gas and in which fraction piperylene is the predominant diolefine constituent, and at least one or a group consisting of drying oil and drying oil acid.

6. A process for the preparation of a synthetic resin comprising reacting a polyhydric alcohol, the adduct of maleic anhydride with a piperylene fraction containing between approximately 30% to piperylene and derived from light oil obtained in the manufacture of combustible gas and in which fraction piperylene is the predominant diolefine constituent, and at least one of a group consisting of drying oil and drying oil acid.

7. A process for the preparation of a synthetic resin comprising reacting ethylene glycol, the adduct of maleic anhydride with a piperylene fraction containing up to approximately piperylene and derived from light oil obtained in the manufacture of combustible gas and in which fraction piperylene is the predominant diolefine constituent, and at least one of 'a group consisting of drying oil and drying oil acid.

8. A process for the preparation of a synthetic resin comprising reacting glyceroLthe adduct of maleic'anhydride with a piperylene fraction containing up to approximately 90% piperylene and derived from light oil obtained in the manufacture of combustible gas and in which traction piperylene is the predominant diolefine constituent, and at least one of a group consisting of drying oil and drying oil acid.

FRANK J. SODAY. 

